PURPOSE: To make a simple and durable constitution as well as to make an actuator small in size by controlling deflection thrust according to the degree of comformity between deflection ports and a rotary ring port of the thrust deflection controller of a flying object.

CONSTITUTION: Exhaust gas burnt inside a rocket motor 1 is injected from a nozzle 2, and when the port 6 of a rotary ring 5 does not conform with deflection ports 7a-7e, it does not generate crosswise thrust, but when they conform with one another, a part of exhaust gas generates crosswise thrust through the rotary ring port 6 and the deflection ports 7a-7e. Therefore, in order to acquire crosswise thrust of desired direction, the rotary ring 5 is rotated by a DC motor 4 installed inside a box (A) through a rotary power transmission section 8 so that the rotary ring port 6 is conformed with any desired positioned deflection ports 7a-7e, with the magnitude of crosswise thrust to be controlled by the degree of conformity between the rotary ring port 6 and the deflection ports 7a-7e. This rotation does not need strong torque, and thus, a simple constitution is possible, and durability is improved.